/**
 * Created by L.jp
 * Description:
 * User: 86189
 * Date: 2022-12-02
 * Time: 0:12
 */
class ListNode {
      int val;
      ListNode next;
      ListNode(int x) { val = x; }
  }
public class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if(l1==null ){
            return l2;
        }
        if(l2==null){
            return l1;
        }
        ListNode head=new ListNode( -1 );
        ListNode cur=head;
        while ( l1!=null && l2!=null ){
            if(l1.val< l2.val){
                cur.next=l1;
                l1=l1.next;
            }else {
                cur.next=l2;
                l2=l2.next;
            }
            cur=cur.next;
        }
        if( l1!=null ){
            cur.next=l1;
        }
        if ( l2!=null ){
            cur.next=l2;
        }
        return head.next;
    }
}
